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EL CANN'CN FURNACE Filed Feb. 28, 1921 2 sheetsheer H. B.. CANNGN v Mh m, mm...

FURNACE z'sneets-Sneet Fild Feb. 28, 1921 kif/1f.

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N@eifrig STATES,

PATENT. OFFICE.-

H RAM B. GNNO, 0F SARNIA, ONTARIO, CANADA, ASSIGNOR TO TEE CARBDBUNDUJ COMPANY, O1? NIAGARA FALLS, `NJEHV YORK, .Al CORPORATEON OF PENNSYLVANIA..

i. nommen Application iledlIjebruary 28, 1,921. Serial No. 448,337.

This inyention relates to furnaces .and to combustion chambers for vfurnaces andthe like..I The general` object of the invention is?` `to providea novel and eilicient furnace and chamberas well asa chamber which is par` ticularly well adapted for the efficient-com# bustion ofpulve'rized fuel as well as for the heating of various objects byl radiation.'

-In the drawing, my 'invention isv shown as adapted to and employed for theheatingl of a steam boiler; but it will be u nderstood4 ,fgirudnal` sectional elevation of a steamlboiler y and furnace embodyingy my i invention lfjig. 2 a sectional'frontelevation,` and Figs.v 3 and 20, 4 are details in' cross section through one-of.

the combustion chambers and-taken respec-V tively at approximately the places indicated by they lines 3-3 and 4-4 on Fig. 1.1

l' Describing the 'var-ions parts by reference characters, 1 denotes the boiler settingjg'enerally, the' same being made'of ordinarylire; brick ,with an inner layer of silica brick or.

other. heat-resisting brick` or material. The Hoor othe setting vslopes downwardly and rearwardly from the front, as indicated at 2, and-the [said setting is providedwith an opening '3 therethrough at thev b )ttom of a trough-,like depression, for a purpose to be described hereinafter. l l s Above'V the boiler setting is a boiler .4, whichy maybe of any standard type, the one shown herein being of the watertube type.

Vithin the chamber .provided in the setting and .between the Hoor 2 and the boiler, 4U there are mounted'a number of my` units suitablefor eiicientlyheating the said boiler.

vEach unit comprises acombustion chamber' 5 formed of a plurality of sections each'composed of .sl-abs of carbo'rundum, this material l5 being used because of its highly refractory nature, its permeability to heat, and -its great capacityv for radiation of heat. AEach combustion chamber is shown as trapezoidal in section and comprises a plurality of sections each lhaving side pieces, each provided with,

an inwardly/*projecting ledge or shoulder 7 a cover piece 8; and 'a bottom' piecel9. The

top and bottom pieces or slabsand the sidc pieces or'slabs arev provided with interflttig 501mg, @indicated a icl-aad similar joints i arerovided between thesections themselves.

If eslred, cement4 of `like material as the.'

slabs `may-be employed at these joints. The

front of eachl combustion chamber 5 iscl'osed i by plate or slab 11 having anlinwardly rejecting ledge 12. The-rearwill be closed.'

y y a specially shaped section 13 forming a concaved back forfthe chamber, for a pur^ posato be explained hereinafter, f The ledges? Aand 12 support "a art-tion which extendsA from the front of t e chem `ber toward, but terminates in front of, `the rear. The partition comprises` a plurality of sections 14, preferably of silicon carbide. The; ledges are so arranged that the front of the partition will be 'supported' below the lcenter of thechamber while the rea-r of the partition 'iis preferably nearly coincidentwith but slightly below such center, the said partition'providing av lower passage, vthe cross-sectional area of which increases from 'the frontgalso an l'upper passage the crosssectional 'area' of which increases from the rear toward the front, the said upper andv 'lowers passages Vcommunicating through the, space provided adjacent tothe rearwall 13 and around the rear lend of the partition.

Toward its rear, the .combustion chamber 1s shaped. to conform to the trough-like 'depression in the Hoor 2, and each of these combustion chambers is provided with a supporting slab 15 resting on the `floor 2, vthe. said slabibeing of refractory material other than silicon carbide,7and provided with projections la adapted to engage the exterior of the combustion chamber and having;A air cirpulating spacesl between the said projecions.

It will be noaa that ai@ bottom Waller he i combustion chamber slopes downwardly from the front to the rear, being provided with a. trough-like depression 17 supported by the like depression in the upper surface of the slab 15.\f The bottom of this depression 17 isprovided with an outlet pipe 18, prefer` ably of carborundum, mounted, within the opening 3 and adapted to discharge-inten ysealed ash pit 19. The bottom ofthe delivery pipe 18 is provided with a damper 20'by means of whichit may be closed lat times when4 it is desired to remove the ashes and ,slag 'from the p it 19, whereby the efficient operation ofv the combustion chamber may is thel material preferably employed for the lll ' bustion chambers Vner to the water tubes of such boiler.

' .wensen not be interrupted. lt will be understood 'that each combustion chamber 5 will be p rovided with its ownA ash pit, whereby the re moral of ashes and slag from any one pit will not interfere with the operation of any other combustion chamber. ISilicon carbide combustion chamber because of its refractory nature and its high thermal conductivity,

such conductivity being in excess of 0.006 cal/cu/sec/OC. Other refractory materials having a thermal conductivity in .excess of that just mentioned are fused aluminum oxide4 (Al-203) and fused magnesium oxide (MgO). ,The combustionehambers thus far described are capable. of general use and par\ ticularly for use with pulverized fuel. Foructs of combustion to be delivered in operative relation to the front of the boiler. lt

vwill be understood that these gaseous prod uctsvwill be directed in any approved man It will be notedthat the combustion cham- I bers are arranged, not only side by side, but

with their sides 6- converging upwardly, wherebygthe sides of each combustion chamber converge from the bottom toward the top l thereof, providing upwardly flaring spaces therebetween. rlhis enables heat radiated at right angles from a wall of one combustion chamber to be'reflected in a most efficient manner from the wall of an adjacent combustion chamber (or other object) resulting in greater eiiiciency than can be obtained where the walls of adjacent chambers are parallel or where the spaces between adjacent chambers taper upwardly.

The combustion ehambersare arranged to cooperate most efficiently with aboilerof the `type shown in Fig. 1, wherein the tubes Il extend rearwardly and downwardly from the front header 4b to the rear header 4t. For the purpose of utilizing the products of com bustion ina most efficient manner7 a' battle ad extends transversely of the tubes a and is located rearwardly of the header ab in such position as to permit thelproductsto be delivered into the flue or space thus formed, as Well asto'enable the tubes to be heated by the part of the combustion chamber therebeneath.` These products of combustion pass above the baille 4d andare directed downbeneath the last mentioned baffle and thence upwardly vto the stack uptake 4g.

` The combustion chambers as described herein,` whilel capable of usewith other fuels,

are particularly adapted for the vefficient combustion of pulverized fuel. Such. fuel will be delivered to the various combustion chambers' by -means of any standard pulverizing and conveying mechanism, each combustion chamber being shown as provided with a burner luardly, by means of batlles le anda, passingl 22, through which the mixture of pulverized fuel and air will be admitted to the respective chambers. Vl`his mixture is ignited and, before the-burning mixture shall have reached the outlets 2l,`the carbon content will have been completely consumed, delivering gases only through said outlets and to the tubes of.

the boiler. In its passage through the combustion chamber, some ashand clinker or slag will beV produced, the amount depending upon the impurities present in the coal or coke. The combustion chamber becomes intensely heated and the temperature of its walls, in conjunction withthe downwardly sloping bottom.y the downward slope of the partition 14 and the construction of the rear end of the chamber, causes all such clnker orslag to be delivered in a molten condition by gravity through the pipe 18 and into the ash pit, without accumulating within or adhering .in any considerable depth to the inner walls of the combustion chamber and hence with-v out injuring the latter and without the formation of such accumulations as would require the opening up or taking down of the combustion chambers from time to time.

Furthermore, the shape of the rear end of the chamber not only facilitates the discharge, of such slag or clinker, but imparts a whirling movement to the gases and particles undergoing combustion, and' thus separates a large proportion of the ash that may result from the combustion of the c oal,coke, or similar material, depositing the ash within the pit 19. i

By the construction described, I have pro duced, within a given length of furnace, a combustionchamber of such length as to insure the complete consumption of the `solid carbon particles aswell as the completecombustion of the resultant gases before the latter reach the openings 21j. 'As a result, there is no accumulation of carbon uponI the boiler tubes and, for reasons pointed out hereinbexfore, there can be no accumulation of slag or clinker upon the same.l

The inclination of the combustion chambers not only secures the advantages pointed out hereinbefore but, where these 4chambers are. made up of various sections, with the rear ends supported solidly against the boiler setting, as indicated, the various sections are retained in operative relation to each other by gravity.

Reference has been made heretofore'to the progressive increase in cross sectional area of the combustion space WithinA each of the chambers 5. This progressive increase tends to maintain substantially constantthe vei .In o'derto permit the combustion chamberl to radiate heat uniformly throughout itsfextent, the thickness ot' the Wallsthereofdifminishes from the frontbr fuel supplying V end towardthe rear. This will be evident from inspection-of Figs. 3 and 4'; the-)tormer of Whichis a section-al View through the combustion chamber near the front end thereof and the latter of which is a similar view taken neary the rear end of .thesaid chamber.

. In order to utilize to the best advantage the heat-radiating and heat-convecting qualities of my combustion chambers, the top wall 44of each suchchamber is substantially continuous throughout its length, the ports 21 being only of such aggregate area 'as'Will' permit the lproducts of combustion to pass between the vboiler tubes Withoutthe development of back pressure. f

In addition, the combustion chambers arel laterally spaced, as shown in Fig. 2, 'whereby thesides operate to heatby radiation andv convection.

combustion chambers are arrangedin close proximity toand parallel 'with theinclin'ed tubes ofthe boiler. 1This resultsiin a. rnaximum eiii'ciency of thecarborun duin vchambers in heating the boiler tubes by radiation and convection'.V i t l v .i

By locating the exhaust outlets 2l at the vfront ofthe-upper. combustion passage, the iame may be caused to travel'tliefull length` of both combustion passages, with the top of higher temperature than is possible wherel 'the flame at such loutlet or outletslf4 `This insurescombustion throughout' thegentire effective length ofthe combustion chamber,- inlcluding the tWo passages. As a result, the combustion chamber Will beuniformly heated t'hronghout'its extent, enabling it to Voperate With lthe inaximuinetiiciency. The crnbustiblemiiiture Within and throughout the length of the upper passage will be heated by the lower passage and `the partition 1li, facilitating thequick and complete combustion of the mixture in the upper passage.

As a result of this construction ,of com bustion chamber,` the latter can be heated to a the exhaust outlets are locatedgat a distance from the front of' the upper passage. and this temperature of the radiating Walls of the Furthermore,the tops ot thel,

'combustion chamber ivill be substantially uniform throughout the entire extentot the combustion chamber, lWhich is also impossible tobe realized in a construction wherein the exhaust outletsxare'located atv a considerable distance Jfronithe front or delivery' A end ofthe combustion chamber. The .higher ,texnperature lwhich can be obtainedrwith the combustion' ,chamber shown herein over that. which .canl-be obtained with any other type or carborundumi combustion chamber with :which Ianiiamiliar, results in a much greater proportional increase in the etiiciency of the installation in which such a chamber .is used, as the heat transferred'by radiation varies with the fourth power of the difference betvveenthe temperature-of the heat-receiving surface (inthis. 'case the boiler) `and the heat radiating surfac'ef. c i Intheb'oilershotvn herein there are a plurality. of series of-tubes in the chamber above the combustion chambers, each series extending transversety of the furnace structure, the lowermost series being in close proximityvto the tops ,of the combustion chambers and the other series being'located above such lowermost series. The tubes in the lowermost series are heated! practically entirely by radiation from the -comtmstion chambers, substantially their entire length. The tubes in the Aseries next above-the lovvermost series will be heated to some extent throughout the y major portion of their length by radiation,

though to a somewhat less extent than is the case with the tubes in the lovvermost series.-

Because of the staggering of the tubes,- the tubes in thel third series Will not be appreciably heated by radiation, but will be appreciably heated practically entirely by conf vection from the-gases discharged from the. combustion chamber While the tubes in tleft series further remote from the tops or roots'V of the combustion chambers Will be heated only by convection.

practically no heating of the lon'ermost series ot tubes by convection except at the iront lends thereof. This arrangement shields the tubes in thelowermost series from ydirect contact with the products of combustion, except at the front'portions thereof; but, because n the-combustion is completed within each corn-k f bustion chamber, the gases discharged frorn the combustion'chamber are at a temperature which Will n ot unduly heat theltubes through convection.

In order that thecombustion chamber .may

radiate heat efiiciently and produce the slagging of the ash, as hereinbefore described, it' must be heated to a temperature offrom about-10000 C. to l-l00O C., Which will render the said chamber incandescent; and this necessitates a combustion rate ot at least 100,000 B. t.- u.s per cu. ft. per hour, which results in the transmissionthrough the Walls Also, because of the shortness of the baffle Wall 4f, there Will bev rio izo

4' Lacasse'- of the combustion chamber and in the radiation from the outer surface thereof of at least 10,000 B. t. Au.s per square foot per hour. Operating at the temperatures mentioned and at the rate of combustion specified, at

. least of the heat resulting from the combustion vwill be transi'nitted by radiation.

, to the boiler tubes.

Having thus described my invention, what 1. A combustion chamber having a partition extending from its frontwall toward and -spaced from its rear wall and dividing said chamber into a lower and an upper com bustionpassage, the lower wall of'said chamber and said partition being inclined down. wardly from the front toward the rear thereof, and the'said chamber having adjacent to the rear thereof,'a delivery outlet communicating with the lower passage, means for .sealing said outlet, means for supplying a .mixture of pulverized fuel and air to theA front of one of the combustion passages, the said combustion chamber being provided with an exhaust outlet adjacent only to the frontof the other combustion passa-ge and the said combustion chamber also being composed principally of a refractorymaterial having a thermal conductivity in excess of 0.0.06 cal/cm/sec/OC.

2. A combustion chamber' having a partivtion extending from its front wall toward and spaced from its rear wall and.dividing A said chamber into a lower and an upper combustion passage, the said combustion chamber. and the said partition being inclined downwardly from the front tothe rear thereof and the said chamber having adjacent the rear thereof a delivery outlet communicating with the lower combustion passage, means for sealing said outlet, means for supplying a mixture of pulverized fuel and air to theI front of the lower combustion passage, the. upper combustion passage being provided with an outlet near the front end only thereof, the said combustion chamber being com- -posed principally of a refractory material having a thermal conductivity in excess of 0.006 cal/cmS/sec/OC.

3. A combustion chamber comprising a plurality of longitudinally/ extending sections each comprising side, bottom and top j slabs, the front section having a front closure slab and the rear section having a rear closure slab, the-. side slabs and the front slab `being provided with seating portions, and a` partition on suchseating portions and extending toward, but spaced from, the rear slab, the said slabs and partitions being composed of a refractory material having a .thermal` conductivity in excess of 0.006

` cal/cm3/sec/C. f v

4. A combustion chamber comprising a plurality ofv longitudinally extending sections e'ach comprising side, bottom and top slabs, the front section having a front clor' sure slab and the rear section having a rear closure slab, the side sections and the front section being provided each with an inward-l lyprjecting ledge, a partition seated upon said ledges, the said ledges being arranged to support the partition in position to provide combustion passages extending from the front closure below said partition, around the rear end ofthe same, and above the said partition, the upper passage having an outlct adjacent to the front vonlyof said .chamber, and means for supplying a combustible mixture to the front of the lower passage,' the saidcombustion chamber and the said' partition being composed principally of` a refractory. material having a thermal con-A ductivity in excess of 0.006 cal/cm3/sec/OC.

5. A. combustion chamber for burning' pulverized fuel, said chamber comprising a pluralityof intermediate sections and a front anda rear section, a partition seated within tom of the said chamber being inclined down-j wardly from the front thereof and having a sealed outlet at the lower end thereof.

6. The combination, with av chambeigof a` series of spaced combustion chambers with- .in said chamber, controllable means for sup plylng a combustible mixture to each of said chambers, the said chambers being placed side by side and each having upwardly convergent side walls providing upwardly .ila-r ing spaces between 'adjacent chambers and between'the chambers at each side`of the series and objects adjacent thereto, each of said chambers being composed principally of a refractory material having a thermal cone ductivity in excess of 0.006 cal/cmS/sec/OC.

7. The combination, with a water tube boiler, of a partition interposed between the front and back of said boiler and providing a vertical liue with such front, a partition or baille interposed between the former partition and the rear ofthe boiler and extend- 'ing downwardly fronn the top thereof, a

combustionl chamber arrangedbeneath the said boiler and having its top or roof substantially co-extens'iveA in length therewith and immediately adjacent thereto,`the said combustion chamber havingintermediate the top and bottom thereofa partition extending from the front. toward and spaced from the rearto provide upper and lower comprovided near its front only with one orL more outlets adapted to dischargeinto the -firstmentioned 'lue the rear end of the upper side of saidl passage being closed and the said chamber beingr composed principally of a refractory material having a .thermal conductivityin excess of 0.006 cal/cma/se'c/GQ and means for supplying a combustible mix-l ture to the front of said 'chamber and beneath said last mentioned partition.

8.v The combination With a combustion chamber and a chamber thereabove, of a series of longitudinally extending tubes arranged within said second mentioned chamber, the

roof of said combustion chamber forming a partitionbetween said chambers and having 1 one or more openings tllerein adjacent 'its forward end only, said series of tubes being arranged above and in close proximity to said roof so as to be heated by radiation therefrom,

a second series of longitudinally extending tubes arranged above said first series, and

`means for causing the products ofcombustion to travel transversely of .said tubes and to heat the same by convection, said combustion cha1nber.being composed principally of a refractory material having a thermal conductivity in excess'of 0.006 cal/cmS/sec/OC.

9. The combination, with vertically spacedy series of longitudinally extending tubes, of

a combustionchamber arranged below said' tubes and having its,top Wall composed of ,a

refractory material having a thermal condiretivity in excess of 0.006 cal/cm/s'ec/OC. and disposed below and adjacentto the lowermost series of tubes and serving to heatthe lowermost tubes' by radiation throu hout substantially their entire length While protecting the same from direct contact With the products of combustion, said top Wall having one or more openings in its forward end only, and means for directing the heated gases of combustion transversely of the tubes whereby to'heatv the same by convection. J y l0. A combustion chamber hav-ing a partition extending from its front Wall `toward .and spaced from its rear Wall'and dividing said chamber into combustion passages arranged on oppositesides of said partition and communicating around the rear end of said partition, the said combustion chamber being inclined downwardly from one end to the other end thereof and having adjacentits" lower enda delivery outlet, means for sealing said outlet, and means for supplying a mixture of pulverized fuel and air to the front of one of the said passages, the other passage being-provided ,with an outlet adjacent the front thereof and one or more of the Walls of said chamber being composed of a refractory material having a thermal conductivityin` excess of 0.006 cal/cma/sec/C.

11; .The combination, With a boiler, of a combustion chamber having a Wall composed' -boiler whereby the boileris heated also by to said boiler whereby the boiler is in position to absorb radiant heat efficiently vfrom such Wall, and means for burning fuel in said combustion chamber thereby to heat the said "Wall` to a degree to cause it to transmit heat rapidly and eiiiciently by radiation to said boiler, said combustion chamber having a plurality of passages, serially arranged, and provided with an exhaust outlet adjacent one end only thereof for 4delivering'wthe gases resulting from combustion in operativerelation tothe j convection from such exhaust gases;

12.'The vcombinatiom'wvith a boiler, of a combustion chamber havingI its `upper Wall in close proximity to said boiler, the said combustion chamber having' an inclined bottom provided at its lower end with an outlet for the discharge of 4molten ash, means for sealing said outlet, means for introducing pulverized fuel into said chamber, the upper Wall of said-chamber extending substantially the full length .of said chamber andbeing com- 4posedprincipally of a'refractory material vvvell as by radiation from the upper Wall of the combustion chamber..

' 1B. The'combination', with a heat absorber, of a combustion chamber having a Wall thereof arranged in close` proximity to said heat absorber and composed principally ofa refractory material having a thermal conductivity `in excess 'fof 0.006 cal/cma/sec/o., said chamber beingprovided With a discharge out 'let for products of vcombustion located adjacent to Aone end only thereof, whereby the said Wall may be heated uniformly throughout its entire extent and eliicient combustion may be 115 secured Within said chamber, the said combustion chamber comprising a plurality of seriallyrelated passages.

14. The combination, With a liquid container, of a combustion chamber having a Wall 120 extending substantially, the fullrlength thereofand arranged in close proximityto said liquid container, said Wall vbeing composed principally of ay refractory material having a thermal conductivity inexcess 4of 0.006 125 cal/cmS/sec/OGand said chamber bein 'pro-` vided With anoutlet adjacent one en only thereof'adapted to deliver products Ofcombustion to contact With vsaid liquid container,

the -said combustion chamberhaving. its bot- 13 tom inclined downwardly and. provided at .its lower end with an outlet leading fto the at- `mosphere and and means for introducing `pulverized fuel means for sealing the saine,

into saidchainber.

15. A combustion chamber having a partition extending from its front wall toward 'and spaced from its rear wall and dividing said chamber into confibustion passages arranged on opposite sides of' said partition and communicating around the rear end of said partition, the said combustion chamber being inolined downwardly from one end to the 4other end thereotl and having adjacent its lower end a delivery outlet, means'for sealing said outlet, and means for supplying a mixture of pulverized fuel and air tothe front of one of the said passages, the' other passage be ing provided with an outlet adjacent the front thereof and one or more of the walls of said chamber being composed principally of silicon carbide'. v,

16. The combination, with a heat absorber, of a combustion chamber having a wall there; of arranged in close proximity to said heat absorber and composed principally of silicon carbide, said chamber being provided with a discharge outlet for products of combustion.

located adjacent to one endv only thereof, whereby the said wall may be heated uniformly throughout its entire extent and eliicient combustion may be secured within saidchamber, the said combustion chamber comprising a pluralityof serially related passage-Y ways.

In testimony whereof, I hereunto aiix my signature.V l u HIRAM BCANNON. 

